Clock



FIG. 1 is a front elevational view of a clock showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof. _

The broken lines shown in FIG. 3 are environmental only, and form no part of my new design. 

The ornamental design for a clock, as shown. 